7: Biochemistry - Lipid anabolism Flashcards
In lipid metabolism, dietary energy is converted into stored ___.
fat
What is lipogenesis?
Fatty acid synthesis
Lipogenesis takes place during (insufficient / excess) energy intake.
excess
In lipogenesis, carbohydrate is converted to which lipids?
Fatty acids
Triglycerides
Which molecule carries triglycerides to adipose tissue?
VLDL
Which protein carries free fatty acids in the plasma?
Albumin
Where does lipogenesis primarily occur?
Liver
Lipogenesis is a (oxidative / reductive) process.
reductive
What is the precursor molecule for lipogenesis?
Acetyl-CoA
Fatty acid breakdown to Acetyl-CoA occurs in the (cytoplasm / mitochondrial matrix).
Fatty acid synthesis from Acetyl-CoA occurs in the (cytoplasm / mitochondrial matrix).
mitochondrial matrix
cytoplasm
Which molecule, usually generated in the TCA cycle, transports acetyl groups into the cytoplasm?
Citrate
Before Acetyl-CoA can convert lipids to carbohydrate, it has to be activated. Which enzyme activates Acetyl-CoA?
Acetyl-CoA carboxylase
What is formed by the activation of acetyl-CoA by acetyl-CoA carboxylase?
Malonyl-CoA
What is the essential regulatory enzyme for the first step of lipogenesis?
Acetyl-CoA carboxylase
What is the activated form of acetyl-CoA which donates a carbon atom to the lipid?
Malonyl-CoA
Which enzyme catalyses the synthesis of long chain fatty acids from malonyl-CoA, acetyl-CoA and NADPH?
Fatty acid synthase
Which protein carries the growing fatty acid chain until sufficient carbon atoms have been added to it?
Acyl-carrier protein (ACP)
What donates electrons to the growing fatty acid chain during lipogenesis?
NADPH
When the length of __ carbons is reached, the newly synthesised fatty acid is released from ACP.
16
What is the regulatory enzyme in lipogenesis?
Acetyl-CoA carboxylase
Which hormone, which signals the fed state, stimulates the activity of acetyl-CoA carboxylase?
Insulin
Which hormone, which signals the starved state, inhibits the activity of acetyl-coA carboxylase?
Glucagon
What is a hormone, other than glucagon, which inhibits the action of acetyl-CoA carboxylase and therefore lipogenesis?
Adrenaline
The concentration of which molecule acts allosterically to switch off lipogenesis when it is high?
Citrate
Which activated form of glycerol is required for triglyceride synthesis?
Glycerol-3-phosphate
In which form is fat stored in adipose tissue?
As triglycerides
